package com.dcm.common.utils;

import java.security.MessageDigest;

/**
 * [MD5工具类]
 *
 * @author : [pengrongsheng]
 * @createTime : [2021/3/29]
 */
public class Md5Encode {
    private final static String[] HEX_DIGITS = { "0", "1", "2", "3", "4", "5","6", "7", "8", "9", "a", "b", "c", "d", "e", "f" };

    public static String getMd5Str(String str) {
        String resStr = "";
        try {
            MessageDigest md = MessageDigest.getInstance("MD5");
            resStr = byteArrayToHexString(md.digest(str.getBytes()));
        } catch (Exception ex) {
            ex.printStackTrace();
        }
        return resStr;
    }
    /**
     * 转换字节数组为16进制字串
     *
     * @param b 字节数组
     * @return 16进制字串
     */
    private static String byteArrayToHexString(byte[] b) {
        StringBuffer resSb = new StringBuffer();
        for (int i = 0; i < b.length; i++) {
            resSb.append(byteToHexString(b[i]));
        }
        return resSb.toString();
    }

    /**
     * byte转换为16进制表示的字符串
     * @param b
     * @return
     */
    private static String byteToHexString(byte b) {
        int n = b;
        if (n < 0) {
            n = 256 + n;
        }
        int d1 = n / 16;
        int d2 = n % 16;
        return HEX_DIGITS[d1] + HEX_DIGITS[d2];
    }
}
